1. The Field of the Invention
This invention relates to tube couplings and in particular to tube couplings comprising coupling bodies to which a tube is connected.
2. The Relevant Technology
A number of arrangements are known for securing tubes to tube coupling bodies. For example our UK Patent Specification No. 1520742 discloses a coupling body having a throughway open at one end to receive a tube with a collet having resilient fingers located in the open end of the coupling body and cooperating with an internal cam surface in the coupling body to cause, with movement of the collet outwardly of the coupling body, the collet arms to be forced inwardly into gripping engagement with the tube to lock the tube in the coupling body. We have a number of subsequent patent specifications disclosing further development of this arrangement including UK patent specification no. 1573757, UK patent specification no. 2131903, UK patent specification no. 2167147 and UK patent specification no. 2172948. These arrangements all deploy a collet of one form or another to lock the tube in the coupling body. Arrangements have also been devised in which the tube is locked in the coupling body by a grab ring such as the arrangement shown in our European patent publication no. 0751329. In this arrangement a grab ring is mounted internally in a coupling body to engage the outer surface of a tube in the coupling body to resist withdrawal of the tube.
The object of the present invention is to provide a simple arrangement for securing a tube to a coupling body which can easily be disconnected and reassembled when required and also allows the user to see the tube has been correctly secured to the coupling body.